Wombat

Wombats are short-legged, muscular quadrupedal marsupials of the family Vombatidae that are native to Australia. Living species are about 1 m (40 in) in length with small, stubby tails and weigh between 20 and 35 kg (44 and 77 lb). They are adaptable and habitat tolerant, and are found in forested, mountainous, and heathland areas of southern and eastern Australia, including Tasmania, as well as an isolated patch of about 300 ha (740 acres) in Epping Forest National Park in central Queensland.

The name "wombat" comes from the now nearly extinct Dharug language spoken by the aboriginal Dharug people, who originally inhabited the Sydney area. It was first recorded in January 1798, when John Price and James Wilson, Europeans who had adopted aboriginal ways, visited the area of what is now Bargo, New South Wales. Price wrote: "We saw several sorts of dung of different animals, one of which Wilson called a 'Whom-batt', which is an animal about 20 inches [51 cm] high, with short legs and a thick body with a large head, round ears, and very small eyes; is very fat, and has much the appearance of a badger." Wombats were often called badgers by early settlers because of their size and habits. Because of this, localities such as Badger Creek, Victoria, and Badger Corner, Tasmania, were named after the wombat. The spelling went through many variants over the years, including "wambat", "whombat", "womat", "wombach", and "womback", possibly reflecting dialectal differences in the Darug language.

Though genetic studies of the Vombatidae have been undertaken, evolution of the family is not well understood. Wombats are estimated to have diverged from other Australian marsupials relatively early, as long as 40 million years ago, while some estimates place divergence at around 25 million years. Some prehistoric wombat genera greatly exceeded modern wombats in size. The largest known wombat, Phascolonus, which went extinct approximately 40,000 years ago, is estimated to have had a body mass of up to 360 kilograms (790 lb).

Wombats dig extensive burrow systems with their rodent-like front teeth and powerful claws. One distinctive adaptation of wombats is their backward pouch. The advantage of a backward-facing pouch is that when digging, the wombat does not gather soil in its pouch over its young. Although mainly crepuscular and nocturnal, wombats may also venture out to feed on cool or overcast days. They are not commonly seen, but leave ample evidence of their passage, treating fences as minor inconveniences to be gone through or under.

Wombats leave distinctive cube-shaped faeces. As wombats arrange these feces to mark territories and attract mates, it is believed that the cubic shape makes them more stackable and less likely to roll, which gives this shape a biological advantage. The method by which the wombat produces them is not well understood, but it is believed that the wombat intestine stretches preferentially at the walls, with two flexible and two stiff areas around its intestines. The adult wombat produces between 80 and 100, 2 cm (0.8 in) pieces of feces in a single night, and four to eight pieces each bowel movement. In 2019 the production of cube-shaped wombat feces was the subject of the Ig Nobel Prize for Physics, won by Patricia Yang and David Hu.

All wombat teeth lack roots and are ever-growing, like the incisors of rodents. Wombats are herbivores; their diets consist mostly of grasses, sedges, herbs, bark, and roots. Their incisor teeth somewhat resemble those of rodents (rats, mice, etc.), being adapted for gnawing tough vegetation. Like many other herbivorous mammals, they have a large diastema between their incisors and the cheek teeth, which are relatively simple. The dental formula of wombats is 1.0.1.41.0.1.4 × 2 = 24.

Wombats' fur can vary from a sandy colour to brown, or from grey to black. All three known extant species average around 1 metre (3 ft 3 in) in length and weigh between 20 and 35 kg (44 and 77 lb).

Male wombats have penile spines, a non-pendulous scrotum, and three pairs of bulbourethral glands. The testes, prostate, and bulbourethral glands enlarge during the breeding season. Female wombats give birth to a single young after a gestation period of roughly 20–30 days, which varies between species. All species have well-developed pouches, which the young leave after about six to seven months. Wombats are weaned after 15 months, and are sexually mature at 18 months.